This blog is intended as an occasional diary of information to feed back to hoverfly recorders in the UK and elsewhere. Inevitably there will be issues of interest that are in some way relevant to invertebrate ecologists and consequently I intend to use the medium as an opportunity to develop thoughts on pertinent topics.

Thursday, 20 March 2014

The question of whether or not it is acceptable to
kill insects in the process of biological recording is one that polarises
views. On the one hand there are some who believe that all records should be
backed up by a pinned specimen; on the other there are those who believe that
nothing should be killed. Some people argue that insects deaths resulting from
impacts with cars is accidental and therefore acceptable; others argue that
roadkill contributes to the overall loss of biodiversity and should be
minimised as far as possible. I fall somewhere in the middle of these views. It
therefore seems to me that there is merit in exploring the various issues in a
bit more detail.

To start with, it is worth thinking about what
biological records are used for, and why so much time, effort and money has
been invested in such initiatives as the National Biodiversity Network, the
Biological Records Centre at Wallingford and the plethora of local records
centres and recording initiatives. Not to mention the armies of volunteers who
undertake everything from the hugely important Wetland Bird Surveys and
Butterfly Monitoring schemes, to national recording schemes, atlas projects and
bioblitzes.

Robust, reliable and up-to-date information is an
essential part of nature conservation. It underpins the site designations that
protect International, national and local wildlife sites. The trends that can
be discerned inform the development of red lists and protected species
legislation. And, of course, trends also influence political thinking. If the
underpinning data are poor, the subsequent analysis will be weak and vulnerable
to attack from those whose interests are threatened by changing legislation and
policy; be that development of marginal land or application of a new form of
pesticide. So, there is an onus on those who compile the data to make them as
robust as possible. In the case of the Hoverfly Recording Scheme, the buck
stops with Stuart Ball and with me. As I tend to do the taxonomic validation of
records, I thought I would set out my thoughts on the issue and explain
howgo about making sure the data are as
robust as realistically possible.

The one reliable way to be absolutely sure
is to only accept records generated by oneself or specimens verified oneself.
Such an approach is impractical, but I am aware of recording scheme organisers
who have taken such a view. Following the latter course means that the dataset
is extremely sparse and probably not sufficiently robust to make statements
about the status of species, either geographically or in terms of abundance and
responses to change. This approach is not viable for the HRS and therefore we
must accept that a small proportion of the data we absorb are incorrectly
identified. As I won't claim to be perfect myself I think I must simply do my
best to establish sufficient rigour to give confidence in the dataset (the man
who thinks he does not make mistakes is either arrogant or too fastidious to be
effective), I therefore use various tests to see whether the submitted data are
accurate.

When we accept records from recorders, we
can make an assessment of their approach, based on the composition of the list
that is submitted. There are obvious clues. For example, there is a well-known
insect ID guidebook that has a very glaring hoverfly identification error in
it. When I see records of that species in the dataset an alarm bell rings and
although we absorb the records into the database they are flagged as questionable
ID - which means the records are never used in analysis. I hope that error
remains in subsequent editions as it is a fantastic marker for one line of
recording! It also means that I have a knowledge of the recorder and can be
vigilant for future records. These data also show how incomplete guidebooks can
have a potentially damaging impact on datasets.

The second clue is whether difficult taxa
are included in the list, and which parts of those assemblages (e.g. Cheilosia,
Sphaerophoria etc) - when I see the gender of certain species included in the
data I know the data has been submitted by somebody who matches specimens to
pictures and does not read and respond to the text. The chances are, therefore,
that they have not used the keys and therefore there can be no certainty about
the validity of the records. Here I flag the easy species as accepted and flag
the others as questionable. In this case, the lesson is that even if people
have the right text books, a proportion will not use them properly and will not
match the standards that the recording scheme organiser has to adhere to.

The third clue is whether or not there has
been validation - either a voucher specimen or a photo. If a voucher
specimenis available,I start to feel
that the recorder is making an attempt to use the very necessary processes of
cross-checking that are needed to deliver reliable data. As long as there is
nothing in the really difficult taxa, then I may well accept the full dataset.
I might want to see specimens/photos for difficult taxa i.e. those we would
class difficulty grades 4 & 5 in our system of validation (1 = generally
safe to accept, 4-5 represent taxa that require very diligent validation). Once
I have seen specimens and have a feel for the competence of the recorder I am
more likely to accept their records immediately. That is, assuming their IDs
are correct. Sometimes I get photos to support records and find that the genus
is wrong and sometimes even the family!

Now, moving on to the value of this
process. It means that the majority of records do get accepted, but that the
dataset is heavily skewed towards commoner and more readily identifiable
species. This presents us with a problem because the scheme has a very strong
link to nature conservation. For example, we use its data to evaluate the
conservation status of hoverflies (which is listed in our book). We can only do
this by having access to data covering the full range of taxa - a sub-set will
not be as valuable to conservation and it could mean that an immensely useful
conservation tool is blunted. That would be a real problem I think.

In addition, datasets that do not include
all taxa also skew the robustness of their use in trend analysis and its
application to developing environmental and policy issues. Complexity of
identification is not a valid analogue for relative abundance. Some very common
species of hoverflies are fiendishly difficult to identify without strong
magnification and examination of characters such as the male terminalia. For
example, as a general rule, the genus Sphaerophoria cannot be identified
beyond generic level without detailed examination and reference to comparative
material.

So, I believe the case is well-made for
rigorous identification and validation processes to make sure that whatever
data are available are reliable. I think we can be reasonably assured that the
majority of the HRS data meet this criterion, but we can never be 100% certain.
Whatever the actual situation is, I feel I can say that the data are screened
to the best level that can be achieved with the resources we have available to
us (i.e. unfunded and usingexperience
of more than 70 years).

Moving on to the issue of road kill. There
are two aspects to this. One is that, if a car is used to make visits to the
countryside, it is almost certain that the drive to and from the site will
involve the death of a number of invertebrates. The numbers today are doubtless
much lower than they were 30 years ago, but they cannot be dismissed as
irrelevant. Consequently, it is possible to compare the careful selection of a
sample of specimens with the indiscriminate impacts of driving the car. Both
lead to the death of a number of invertebrates.

The collection of specimens is a very
deliberate decision to capture and kill animals. As such it can be judged
because the decision has been made to kill; it is not an incidental result of a
more legitimate process that can be justified for personal reasons - or is it?

In the case of animals killed by cars the
question arises as to whether these deaths are accidental by-products of a
legitimate activity. Those advocates who argue that theyare not deliberately killed overlook the fact
that a clear decision has been made to drive the car. Making that decision
means that we also make the decision to knowingly kill insects (everybody has
experienced the thud of an insect hitting the windscreen, followed by the trail
of ooze that paints the screen with the animal's remains).

An example that ought to resonate with
readers is the problem of recording bumblebees. I stopped recording bumblebees
a long while ago because I cannot do them without killing them. But, we might
all help if we picked up these roadkill and submit them to a scheme (I have
long held that walking roadsides and collecting bumblees killed by cars might
be a good way of looking at the effects of roads on bumblebee populations). The
point of course is that without valid data, bumblebee conservation will lack
the critical tool to influence policy and raise the profile of bumblebee
conservation.

Looking at these two scenarios, it seems to
me that it is not possible to make a value judgment about the acceptability of
killing specimens without also asking whether it is acceptable to drive a known
killing machine and regard the deaths of countless insects as an acceptable
legitimate by-product. If specimens are killed and the data that result are
used for a valid purpose, including wildlife conservation, it is surely no
worse than driving your car to go to work, for a country visit or to shop in
the out of town hypermarket? And, it should also be remembered that the lorry
that delivers food to the shop will also have killed insects.

It therefore seems to me that we cannot
really absolve ourselves from the processes that kill insects. There is a
paradox that involves value judgments about the differences between the two
activities. Cars lead to betterment of our minds, bodies and happiness above
whereas the production of the highest quality evidence that MIGHT be useful in
changing land management policies.

There are two ways of addressing this
issue. Firstly, if convinced that there is a need for taxonomically rigorous
data, we can make appropriate collections of invertebrates with the expressed
intentions of contributing rigorously assembled data to a scheme that does set
out to help influence policy. Those who remain uncomfortable with deliberate
killing of insects can still do their best to provide details of what they see,
at a level of validation that is consistent with their value judgments. There
is no compunction to take specimens, especially as for most people the primary
objective of a countryside visit is a nice day out and improvement of the mind
and body. I would argue that everybody, however, has a responsibility to make sure
that the indiscriminate deaths of insects are minimised or or are ameliorated
by improving the body of information that might help to save wildlife.

I would therefore argue that where the car
is used to visit the countryside, one should also participate in whichever
recording schemes fit our interests in the natural environment. It might be as
a birder - if so, perhaps contributing to WeBs counts, breeding bird surveys or
other initiatives. If so, added value might be the incidental (accurate) records
of other taxa observed in the course of the day out. Alternatively, it might be
conducting butterfly transects and noting the occasional beetle, hoverfly etc.
Or, it might be compiling a comprehensive photographic record of the insects
visiting a particular site. Critically, unwillingness to kill animals indicates
a love for the natural world, and what better way to love it than to make a
contribution to the science that might help to conserve it!

So, with that I will sign off by
emphasising that everybody can make a valid contribution to conservation by
making their trips into the natural world count for as much as possible. If
datasets are strong, then the evidence placed before politicians becomes more
powerful. That in turn gives the natural world a fighting chance, providing it
has technically competent advocates who can present a compelling and
evidence-based argument. We therefore need the taxonomically rigorous recorder
as much as we do those who prefer to avoid collecting.

The natural world is there to be valued. It
enriches lives and is the life-support system for the planet. Our
responsibility is to therefore to protect it, and to provide it with the
defence mechanisms it needs to survive the ravages of man's worst excesses.

About Me

An ecologist with over 30 years experience in statutory nature conservation and biological recording. I am now an independent coastal management consultant (Bright Angel Coastal Consultants Ltd.) and have undertaken commissions in the UK and several northern European countries. I originally trained as an entomologist and parasitologist. Today, I retain an interest in entomology but in a strictly non-vocational capacity. In my non-working time I am joint organiser of the Hoverfly Recording Scheme (with Dr Stuart Ball) and am extremely committed to developing new capacity in insect identification and biological recording.